Powder metallurgy production method for components

Abstract

The invention relates to a method for powder metallurgical production of a component (11) made of a first powder (2) and a second powder (3). By filling the first powder (2) into a mold (4) so ​​that the outer contact surface (5) of the first powder (2) forms an angle (7) of 55° to 65° with the axis (6) of the subsequent green product (1), a simplified production and improved definition of the component (11) are achieved, wherein the second powder (3) is subsequently filled into the mold (4) and the green product (1) is generated. The green product (1) is sintered to generate the component (11). In addition, the invention relates to a device (12) having a component (11) and a structure (13) generated in this way.

Description

Technical Field

[0001] The invention relates to a method for the powder metallurgical production of a component. In addition, the invention relates to an arrangement having components and structures produced in this way. Background Art

[0002] To produce metal or metal-containing components, metal powders are frequently used, from which the component is produced in a suitable powder metallurgy process, in particular by sintering.

[0003] It is known that the metallurgical powders used in the production of such components are different from each other. It is thus possible to combine the different properties of the various powders. For example, it is desirable to provide one powder, after sintering, to adjoin another sintered powder in a subsequent component. Considered here are such components that are loaded on their outside, wherein the less resistant sintered powder forms the core and the more resistant sintered powder forms the outside of the component.

[0004] For this purpose, a first metallurgical powder may be introduced into a mold. Subsequently, a second metallurgical powder may be introduced into the mold and contacted with the outer contact surface of the first powder. Subsequently, the powder is pressed to produce a green product. Subsequently, the green product is sintered to produce a component. In this process, during the refinement of the powder, an undefined transition may occur between the two powders and thus a mixing of the two powders may occur. This may lead to poor and unfavorable properties of the subsequent component.

[0005] Furthermore, in the known method, a first powder is introduced into a mold and pre-pressed. Subsequently, a second powder is introduced into the mold so that the second powder is in contact with the outer contact surface of the first powder. Subsequently, the two powders are pressed to produce a green product and subsequently sintered to produce a component. This improves the transition between the two powders, but also means an increased cost for producing the component. Summary of the invention

[0006] The invention therefore has for its object to specify a method for the powder metallurgical production of a component of the type mentioned at the outset, as well as an arrangement having such an improved component and structure, or at least other embodiments characterized by simplified production and / or increased resistance.

[0007] The invention is based on the general idea that during the production of a component made of two different metallurgical powders, first the first powder is introduced into the mold and subsequently the second powder is introduced into the mold, and in the transition region between the two powders an angle of 55° to 65° relative to the axis of the green product produced from the powders is provided. In-depth investigations surprisingly showed that such an angle between the powders leads to a well-defined transition of the first powder into the second powder, in particular without pre-pressing the first powder, i.e. in particular it is necessary to mold the first powder with forces of up to 65 MPa. Thus, according to the idea of ​​the invention for simplified production, a well-defined transition is produced between the two powders in the green product, whereby the subsequent component is well-defined, which component in particular has improved mechanical stability.

[0008] According to the concept of the present invention, a mold for producing the component is provided. First, a first metallurgical powder is filled into the mold. This is to make the outer contact surface of the first powder in the mold form an angle of 55° to 65° with the axis of the subsequent green product. Subsequently, a second powder is filled into the mold. The second powder is filled into the mold so that the second powder abuts the contact surface of the first powder. Subsequently, a green product is generated, and a component is generated from the green product by sintering.

[0009] The production of the green product is actually carried out by pressing the powder. Here, the powder is preferably pressed together. In other words, before the second powder is filled into the mold, the first powder does not need to be pre-pressed, although this is conceivable.

[0010] The contact surface of the first powder forms an internal contact surface in the green product between the powders. The contact surface thus defines the boundary surface between the two powders and thus defines the boundary surface between different and interconnected parts of the subsequent component generated from the powders by sintering.

[0011] To produce the component, further processing can be performed after sintering of the green product. In particular, it is conceivable to perform a heat treatment after sintering. It is also conceivable to produce a molded part after sintering, which is then reprocessed to its final dimensions to produce a component.

[0012] Particularly preferably, the method according to the invention is used to produce rotationally symmetrical green products, and moreover preferably rotationally symmetrical components which are rotationally symmetrical about an axis. This makes the production of the component particularly simple and the transition between the powder in the mold and in the green product, and thus the parts in the component, precisely defined.

[0013] An embodiment in which the contact surface of the first powder forms an angle of about 60° with the axis is considered to be advantageous. This angle has proven to be particularly advantageous with respect to a clear transition zone between the powders. In particular, the angle is 58° to 62°.

[0014] In an advantageous embodiment, the sintered second powder forms the outside of the component and thus at least partially covers the sintered first powder. In particular, the sintered first powder and thus the first part formed the core of the component, while the sintered second powder and thus the second part formed the outside of the component. In other words, the first part of the component is the core of the component, while the second part is the outside of the component. Thus, in particular the first powder can be selected more economically, in particular a first powder that is less resistant than the second powder. In particular, the first powder can be selected as a carrier material and the second powder as a functional material of the subsequent component.

[0015] Advantageously, the powders are selected such that the sintered second powder and thus the resulting second part have a higher wear resistance than the sintered first powder and thus the resulting first part. This enables a particularly cost-effective production of the component.

[0016] In general, a component can be any object.

[0017] The variant in which the component is a tribologically loaded component is considered to be advantageous. In this case, the sintered second powder and thus the second part or the outer side are preferably exposed tribologically in the associated device.

[0018] In the device, the component interacts with another component, wherein, for better distinction, the other component is referred to as a structure in the following text. Here, the second part in the device, namely the sintered second powder, is in frictional contact with the structure.

[0019] It is conceivable to produce a ring as a component, for example a piston ring, which interacts with a cylinder as a structural body.

[0020] It is conceivable to produce a valve seat insert as a component which interacts with the valve as a structural body.

[0021] Here, it should be understood that, in addition to the method for producing a component, such an apparatus is also part of the scope of the present invention.

[0022] Basically, structures can be made from any material.

[0023] Preferably, the structure is based on iron and / or nickel.

[0024] Alternatively or additionally, it is advantageous if the structure is coated with a protective coating and / or is nitrided.

[0025] In general, each metallurgical powder may have any composition, wherein the composition of the second powder having and / or having the resulting increased resistance compared to the composition of the first powder is preferred.

[0026] Embodiments in which the first powder has the following composition are considered to be advantageous: C: 0.3 to 1.8 wt. %; Si: 0 to 1.8 wt. %; S: 0 to 1.0 wt. %; Mn: 0 to 1.0 wt. %; Cr: 0 to 15.0 wt. %; Mo: 0 to 2.5 wt. %; Cu: 5 to 48 wt. %; Ni: 0 to 3.5 wt. %; W: 0 to 5.5 wt. %; V: 0 to 2.0 wt. %; the remainder being Fe and production-related contaminants. Here, "wt. %" represents a weight percentage or a mass ratio.

[0027] In particular, the first powder has the following composition: C: 0.5 to 1.8 wt%; Si: 0 to 1.8 wt%; S: 0 to 1.0 wt%; Mn: 0 to 0.6 wt%; Cr: 3.0 to 15.0 wt%; Mo: 2.5 to 5.0 wt%; Cu: 12.0 to 20.0 wt%; Ni: 0 to 3.5 wt%; W: 0.5 to 5.5 wt%; V: 0.4 to 2.0 wt%; the remainder is Fe and production-related contaminants.

[0028] The first powder may also have the following composition: C: 0.5 to 1.5 wt. %; Si: 0 to 0.8 wt. %; S: 0 to 1.0 wt. %; Mn: 0 to 1.0 wt. %; Cr: 0 to 1.0 wt. %; Mo: 0 to 1.0 wt. %; Cu: 28.0 to 48.0 wt. %; Ni: 0 to 1.0 wt. %; the remainder being Fe and production-related contaminants.

[0029] Furthermore, it is conceivable that the first powder has the following composition: C: 0.3 to 1.3 wt. %; Si: 0 to 0.8 wt. %; S: 0 to 0.5 wt. %; Mn: 0 to 1.0 wt. %; Cr: 0 to 1.0 wt. %; Mo: 0 to 2.0 wt. %; Cu: 5.0 to 15.0 wt. %; Ni: 0 to 3.5 wt. %; the remainder being Fe and production-related contaminants.

[0030] Preferably, the second powder has the following composition: C: 0.7 to 1.8 wt%; Si: 0 to 1.8 wt%; Mn: 0 to 1.0 wt%; S: 0 to 0.5 wt%; Cr: 2.0 to 15.0 wt%; Mo: 2.5 to 18.0 wt%; V: 0.4 to 2.0 wt%; Cu: 10.0 to 20.0 wt%; W: 0.8 to 4.0 wt%; Co: 0 to 12.0 wt%; Ni: 0 to 3.5 wt%; the remainder is Fe and production-related contaminants.

[0031] For example, the second powder can have the following composition: C: 1.0 to 1.8 wt%; Si: 0.2 to 1.8 wt%; Mn: 0 to 0.6 wt%; S: 0 to 0.5 wt%; Cr: 10.0 to 15.0 wt%; Mo: 2.5 to 4.5 wt%; V: 0.4 to 1.0 wt%; Cu: 12.0 to 20.0 wt%; W: 0.8 to 1.5 wt%; Co: 0 to 2.0 wt%; Ni: 0 to 3.5 wt%; the remainder being Fe and production-related contaminants.

[0032] Alternatively, the second powder can have the following composition: C: 0.7 to 1.5 wt%; Si: 0 to 1.0 wt%; Mn: 0 to 1.0 wt%; S: 0 to 0.5 wt%; Cr: 2.0 to 4.0 wt%; Mo: 12.0 to 18.0 wt%; V: 1.0 to 2.0 wt%; Cu: 10.0 to 20.0 wt%; W: 2.0 to 4.0 wt%; Co: 8.0 to 12.0 wt%; Ni: 0 to 3.5 wt%; the remainder being Fe and production-related contaminants.

[0033] Preferably, during sintering, i.e. during the sintering operation, the green product is infiltrated with copper or a copper alloy. This results in an increased mechanical stability of the component. In particular, pure copper or a copper alloy having a copper content of at least 70% by weight is used.

[0034] Further important features and advantages of the invention will emerge from the drawings and the associated description of the figures with the aid of the drawings.

[0035] It is to be understood that the features mentioned above and still to be explained below can be used not only in the respectively stated combination but also in other combinations or alone, without departing from the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Preferred exemplary embodiments of the invention are shown in the drawings and are described in more detail in the following description, wherein the same reference numerals relate to identical or similar or functionally identical components.

[0037] In each case it is schematically shown,

[0038] Figure 1 is a cross-sectional view of a green product having two metallurgical powders,

[0039] Figure 2 is a cross-sectional view of a green product in another exemplary embodiment,

[0040] Figure 3 is a cross-sectional view of a green product in yet another exemplary embodiment,

[0041] Figure 4 are cross-sectional views of devices having components and structures generated from green products. DETAILED DESCRIPTION

[0042] For production Figure 4 The component 11 shown by way of example in the example, is first produced such as Figures 1 to 3 The green product 1 is shown in FIG.

[0043] To produce a green product 1, a first metallurgical powder 2 and a second metallurgical powder 3 different from the first metallurgical powder 2 are filled into a mold 4, wherein: Figures 1 to 3 The states in which the two powders 2 and 3 have been filled into the mold 4 are shown respectively. Here, the first powder 2 is first filled into the mold 4. This is so that the outer surface 5 of the first powder 2 (hereinafter also referred to as the contact surface 5) forms an angle 7 of 55° to 65°, preferably 58° to 62°, and particularly preferably 60° with the axis 6 of the green product 1 (particularly preferably the subsequent component 11). Subsequently, the second powder 3 is filled into the mold 4 so that the second powder 3 is adjacent to the contact surface 5 and is in contact with it.

[0044] Subsequently, the green product 1 is produced by jointly pressing the powders 2, 3. Subsequently, the green product 1 is sintered to produce the component 11. In this process, it is conceivable that during sintering, the green product 1 is infiltrated with copper or a copper alloy having a content of at least 70% by weight. After sintering, the component 11 or the molded part (not shown) produced from the green product 1 can be heat treated. When a molded part is produced from the green product 1, the molded part is reworked to adjust the dimensions to produce the component 11.

[0045] In the exemplary embodiment shown, the green product 1 and the subsequent component 11 are rotationally symmetrical with respect to the axis 6 .

[0046] The sintered first powder 2 in the component 11 forms the first portion 8 as the core 9 of the component 11. In contrast, the sintered second powder 3 forms the second portion 10 of the component 11 and is disposed outside the component 11, thereby forming the outer side 20 of the component 11.

[0047] according to Figure 4 Component 11 is preferably a component that is in frictional contact with an associated component 13 in an associated device 12, which is also referred to below as a structure 13 for better distinction. In particular, component 11 can be a ring 14, such as a valve seat insert 15. In device 12, valve seat insert 15 is in frictional contact with valve 21 as structure 13.

[0048] Preferably, the second powder 3 sintered to form the second loading portion 10 of the component 11 is more resistant than the first powder 2. The first powder 2 or sintered first powder 2 is the carrier material 16 of the component 11 and the second powder 3 or sintered second powder 3 is the functional material 17 of the component 11.

[0049] The first powder 2 and the carrier material 16 obtained therefrom can have the following composition: C: 0.3 to 1.8 wt. %; Si: 0 to 1.8 wt. %; S: 0 to 1.0 wt. %; Mn: 0 to 1.0 wt. %; Cr: 0 to 15.0 wt. %; Mo: 0 to 2.5 wt. %; Cu: 5 to 48 wt. %; Ni: 0 to 3.5 wt. %; W: 0 to 5.5 wt. %; V: 0 to 2.0 wt. %; the remainder being Fe and production-related contaminants.

[0050] The second powder 3 and the functional material 17 obtained therefrom can have the following composition: 0.7 to 1.8 wt. %; Si: 0 to 1.8 wt. %; Mn: 0 to 1.0 wt. %; S: 0 to 0.5 wt. %; Cr: 2.0 to 15.0 wt. %; Mo: 2.5 to 18.0 wt. %; V: 0.4 to 2.0 wt. %; Cu: 10.0 to 20.0 wt. %; W: 0.8 to 4.0 wt. %; Co: 0 to 12.0 wt. %; Ni: 0 to 3.5 wt. %; the remainder being Fe and production-related contaminants.

[0051] The structure 13 is preferably based on iron and / or nickel. The structure 13 may have a protective coating (not shown) and / or be nitrided.

[0052] In the exemplary embodiment shown, the contact surfaces 5 each extend rotationally symmetrically with respect to the axis 6. Figure 1 and Figure 2 In the exemplary embodiment of , the contact surface 5, which forms an angle 7 of 55° to 65° with the axis 6, extends over the entire outer side of the first powder 2. In contrast, the contact surface 5 Figure 3In the exemplary embodiment of the present invention, the flat side 18 of the first powder 2 is limited, i.e., does not extend over the entire outer side of the first powder 2. In the present exemplary embodiment, the flat side 18 of the first powder 2 adjoins the contact surface 5, which forms an angle of 55° to 65° with the axis 6. Here, the flat side 18 is arranged on the inner side of the contact surface 5 and is smaller than the contact surface 5.

[0053] exist Figure 2 and Figure 3 In the exemplary embodiment of , a groove 19 is provided in the green product 1 and in the subsequent component 11 obtained therefrom. Figure 1 In the exemplary embodiment of , no such recesses 19 are provided in the green product 1 and in the subsequent component 11 obtained therefrom.

Claims

1. A powder metallurgy production method for a component (11), the method comprising: - providing a mold (4), - filling the first metallurgical powder (2) into the mold (4) such that the outer contact surface (5) of the first metallurgical powder (2) in the mold (4) forms an angle (7) of 55° to 65° with the axis (6) of the subsequent green product (1), - filling a second metallurgical powder (3) different from the first metallurgical powder (2) into the mold (4) so ​​that the second metallurgical powder (3) is adjacent to the contact surface (5) of the first metallurgical powder (2), wherein the first metallurgical powder (2) is not pre-compressed before the second metallurgical powder (3) is filled into the mold (4), - generating the green product (1) from two powders (2, 3), - Sintering the green product (1) to produce the component (11).

2. The method according to claim 1, characterized in that The component (11) is generated to be rotationally symmetrical with respect to the axis (6).

3. The method according to claim 1 or 2, characterized in that: The component (11) is produced such that the sintered second metallurgical powder (3) forms an outer side (20) of the component (11) and at least partially covers the sintered first metallurgical powder (2).

4. The method according to any one of claims 1 or 2, characterized in that: The first metallurgical powder (2) is filled into the mold (4) so ​​that the contact surface (5) forms an angle (7) of 58° to 62° with the axis (6).

5. The method according to claim 1 or 2, characterized in that: A powder having higher wear resistance than the first metallurgical powder (2) in the component (11) is used as the second metallurgical powder (3).

6. The method according to claim 1 or 2, characterized in that: A friction loaded component (11) is produced, wherein a sintered second metallurgical powder (3) of the component (11) is frictionally exposed and a sintered first metallurgical powder (2) carries the sintered second metallurgical powder (3).

7. The method according to claim 1 or 2, characterized in that: During sintering, the green product (1) is infiltrated with copper or a copper alloy having a copper content of at least 70% by weight.

8. The method according to claim 1 or 2, characterized in that: A first metallurgical powder (2) having the following composition is used: -C: 0.3 to 1.8% by weight -Si: 0 to 1.8 wt %, -S: 0 to 1.0% by weight - Mn: 0 to 1.0 wt %, -Cr: 0 to 15.0% by weight - Mo: 0 to 2.5 wt %, -Cu: 5 to 48% by weight -Ni: 0 to 3.5 wt %, -W: 0 to 5.5% by weight -V: 0 to 2.0% by weight - The remainder is Fe and production-related contaminants.

9. The method according to claim 1 or 2, characterized in that: A second metallurgical powder (3) having the following composition is used: -C: 0.7 to 1.8% by weight -Si: 0 to 1.8 wt %, - Mn: 0 to 1.0 wt %, -S: 0 to 0.5% by weight -Cr: 2.0 to 15.0% by weight - Mo: 2.5 to 18.0 wt %, -V: 0.4 to 2.0% by weight -Cu: 10.0 to 20.0 wt %, -W: 0.8 to 4.0% by weight - Co: 0 to 12.0% by weight -Ni: 0 to 3.5 wt %, - The remainder is Fe and production-related contaminants.

10. A device (12) having a component (11) produced by a method according to any one of claims 1 to 9 and a structure (13) based on iron and / or nickel, wherein: The outer side (20) of the component (11) formed of the sintered second metallurgical powder (3) is in frictional contact with the structure (13).

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